About 95% of the commercial use of silicon dioxide (sand) occurs in the construction industry, e.g., for the production of concrete (Portland cement concrete). Certain deposits of silica sand, with desirable particle size and shape and desirable clay and other mineral content, were significant for sand casting of metallic products. The high melting point of silica enables it to be used in such applications as iron casting; modern sand casting sometimes uses other minerals for other reasons. Crystalline silica is used in hydraulic fracturing formations containing tight oil and shale gas. The precursor to glass and silicon: Silica is the primary ingredient in the production of most glass. As other minerals are melted with silica, the principle of freezing point depression lowers the melting point of the mixture and increases fluidity. The glass transition temperature of pure SiO2 is about 1475 K. When molten silicon dioxide SiO2 is rapidly cooled, it does not crystallize but solidifies as glass. Because of this, most ceramic glazes have silica as the main ingredient. The structural geometry of silicon and oxygen in glass is similar to that in quartz and most other crystalline forms of silicon and oxygen, with silicon surrounded by regular tetrahedra of oxygen centers. The difference between the glass and crystalline forms arises from the connectivity of the tetrahedral units: Although there is no long-range periodicity in the glassy network, ordering remains at length scales well beyond the SiO bond length. One example of this ordering is the preference to form rings of 6-tetrahedra. If you are looking for high quality, high purity, and cost-effective Silicon dioxide, or if you require the latest price of Silicon dioxide, please feel free to email contact mis-asia.